1. Field of the Invention
The present invention relates to a recording tape cartridge which rotatably accommodates a reel on which a recording tape, such as a magnetic tape or the like, is wound.
2. Description of the Related Art
Recording tapes, such as magnetic tapes and the like, are used as external recording media for computers and the like. Recording tape cartridges are used which accommodate a single reel on which is wound a recording tape which requires little space for storage and on which a large amount of information can be recorded. In a recording tape cartridge, a single reel on which a recording tape is wound is rotatably accommodated within a case which is formed by joining together an upper case and a lower case which are molded of a resin material. An opening is formed in the case. The recording tape is pulled-out from this opening, and is taken-up onto a take-up reel of a drive device.
The opening is opened and closed by a door which is a shielding member, so that dust and the like do not enter in from the opening and adhere to the recording tape. Namely, when the recording tape cartridge is not in use, the opening is closed by the door. When the recording tape cartridge is to be used, the door is moved such that the opening is opened.
As a recording tape cartridge equipped with a door, a structure is known which is provided with an opening provided in a side wall of a case which side wall runs along the direction of loading the recording tape cartridge into a drive device, a door which slides at the inner side of the side wall and along the loading direction so as to open and close the opening, a spring urging the door in a direction of closing the opening, and an operation portion which is provided at the door and which, due to the operation of the case being loaded into a drive device, slides the door in the direction of opening the opening while engaging with an opening/closing member of the drive device.
In accordance with this structure, merely by the operation of loading the case (i.e., the recording tape cartridge) into the drive device, the operation portion provided at the door slides the door with respect to the case while engaging with the opening/closing member which is fixed to the drive device (i.e., which moves relatively to the case), such that the opening is opened. In this way, it suffices to merely fix the opening/closing member at a position of the drive device at which the opening/closing member can engage with the operation portion, and the structure is simple.
However, in the above-described conventional recording tape cartridge, when the operation portion of the door engages the opening/closing member of the drive device at the time of opening the opening, a rotational moment around the region of this engagement arises, and a problem arises in that the case (i.e., the recording tape cartridge) rotates around this region of engagement and becomes tilted with respect to the direction of loading. In particular, because the opening is opened against the urging force of the spring, this rotational moment (the pushing-in force in the loading direction) is large, and it is easy for the case to become tilted within the drive device (it is easy for the position of the case to become offset).
If the case is pushed into the drive device in this state, there is the concern that the case will rub against the interior of the drive device, and the case will become scratched or abrasion powder will be generated within the drive device, or the case will become stuck within the drive device.
Thus, in order to offset this rotational moment, a structure has been conceived of in which an engagement member of the drive device is engaged with a position, of the loading direction leading side surface (the front surface) of the lower case, which position is set apart from the side wall in which the opening is formed. While this engaged state is maintained, the case (together with the engagement member) move in the loading direction and open the opening.
However, in a case which is formed by joining together an upper case and a lower case molded of a resin material as described above, the outer surface which includes the aforementioned front surface is a design surface at which crimping processing and the like are carried out, and the draft for removing the case from a mold after molding is large and the dimensional accuracy is low. When the engagement member is engaged at a position of this front surface of the case which position is set apart from the opening, at the case, the aforementioned rotational moment is offset, but the positional accuracy of the opening with respect to the drive device (which is most important in terms of function) is low. Moreover, in a recording tape cartridge having the above-described structure, movement in the direction of pulling the case out from the drive device is permitted. Thus, there are cases in which positional offset of the case (the opening) with respect to the drive device occurs due to the urging force of the spring which urges the door, or the like.
Japanese Patent Application Laid-Open (JP-A) No. 2000-331403 has disclosed a structure in which a lock hole, which an anchor means (a lock block or the like) engages, is formed at the case. The anchor means is for preventing the recording tape cartridge from being pulled-out from the drive device. After the opening is opened, the anchor means anchors the recording tape cartridge to the drive device. When the aforementioned positional offset occurs at the point in time when the opening is opened, there are cases in which the anchor means does not correctly engage with the lock hole. Moreover, with an anchor means which anchors the case after the opening has been opened, the aforementioned rotational moment cannot be offset.
Further, in an automatic cartridge conveying device (a library device), a large number of recording tape cartridges are accommodated individually in holder portions, and are automatically conveyed from the holder portions to drive devices as needed. However, in this case as well, with a conventional recording tape cartridge, movement in the direction of pulling the cartridge out from the holder portion is permitted. Thus, there are cases in which positional offset of the case with respect to the holder portion arises.